Thermal-neutron reactor

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Main article: Nuclear reactor

A thermal reactor is a nuclear reactor that uses slow or thermal neutrons. ("Thermal" does not mean hot in an absolute sense, but means in thermal equilibrium with the medium it is interacting with, the reactor's fuel, moderator and structure, which is much lower energy than the fast neutrons initially produced by fission.)

Most nuclear power plant reactors are thermal reactors and use a neutron moderator to slow neutrons until they approach the average kinetic energy of the surrounding particles, that is, to reduce the speed of the neutrons to low velocity thermal neutrons. Neutrons are uncharged, this allows them to penetrate deep in the target and close to the nuclei.[1] Thus scattering neutrons by nuclear forces, some nuclides are scattered large.[1]

Nuclear fissions are most prevalent with slow neutrons which help sustain the chain reactions in nuclear reactors. Fission is dependent upon the energy available within the neutrons of an atom. Essentially, if you were able to extract the energy from the neutron of the atom you could sustain high levels of electric output from the reactor. Which, in turn, would produce more usable energy in our economy.

The upsides to having this type of energy present in our economy is that we have immense percentages of our allocated energy generated through these types of entities. 63.3% of our emission free electricity is produced through nuclear reactors. Also, with the US nuclear industry we have reduced toxins in our environment and are currently making more efficient and environment-friendly solutions to producing such energy (NEI).

The nuclear cross section of uranium-235 for slow thermal neutrons is about 1000 barns, while for fast neutrons it is in the order of 1 barn.[2] Therefore thermal neutrons are more likely to cause uranium-235 to fission than to be captured by uranium-238. If at least one neutron from the U-235 fission strikes another nucleus and causes it to fission, then the chain reaction will continue. If the reaction will sustain itself, it is said to be critical, and the mass of U-235 required to produce the critical condition is said to be a critical mass.

Thermal reactors consists of the following:

See also[edit]


The control of a thermal neutron reactor Moore, R.V. Proceedings of the IEE - Part I: General Volume: 100, Issue: 123 DOI: 10.1049/pi-1.1953.0032 Publication Year: 1953 IET JOURNALS & MAGAZINES